The present invention relates to a drive for a disk (a recording medium in a disk shape) such as a CD-ROM, and more particularly to decelerating and stopping control of a motor which rotates the disk.
In a disk device 20 such as a CO-ROM drive having components shown in FIG. 2, when a disk motor driver 23 receives a command to decelerate or stop rotation of a disk 22 from a controlling means (CPU) 21 of the disk device 20, a reverse-direction voltage is applied from a disk motor driver 23 to disk motor 24 to exert a forced braking force for rapid deceleration. In the case where rotation of the disk motor 24 is decelerated by applying the reverse-direction voltage to the disk motor 24 to put on a brake as described above, that is, rotation of the disk motor 24 is decelerated in a so-called normal mode, current consumption is considerably high and the disk device 20 used in a portable computer, which-is required to save power, is affected significantly. Reference numeral 25 in FIG. 2 denotes a signal processing system provided in the disk device 20 and reference numeral 26 denotes a host computer for managing the disk device 20.
Added to the conventional disk device 20 are power saving functions such as a low-rotation mode and standby mode in light of enhancing the power saving effect. These are the functions of suppressing the power consumption by lowering a rotational speed of the disk motor 24 or bringing the disk motor 24 to a stop condition in compliance with decision by the CPU 21 when no access command such as a read command or seek command is issued by the host computer 26 for a predetermined time. In the portable computer, therefore, a shift to the low rotation mode or sleep mode is often produced and the fact that the high current is consumed by the deceleration of the disk motor 24 for each movement causes trouble.
Japanese Patent Laid-Open No. 11-96649 discloses a disk drive device of a configuration such that in the disk drive device for applying the reverse-direction voltage to a disk motor which rotates a disk to be forcedly stopped, the application of the reverse-direction voltage is suppressed in a power saving mode to inertially rotate the disk motor to be stopped. It also discloses a method of enhancing power saving effect without consuming high current for each shift to the sleep mode by inertially rotating the disk motor in a sleep mode also in a disk drive which shifts from a normal mode to the sleep mode to bring the disk motor to a stop condition when there is no access to the disk for a predetermined time.
As a method of rapidly decelerating and stopping the disk in lower power consumption, Japanese Patent Laid-Open No. 9-285174 discloses a method of decelerating the rotational speed of the disk by bringing a coil of a motor driver IC to a short-circuit condition during the deceleration and utilizing a reverse electromotive force of the motor and a method of compensating for reduction of the braking force at a portion where the reverse electromotive force at the time of a low rotation is reduced in combination with a reverse brake during the stop of the rotation.
However, in the disk drive device disclosed in Japanese Patent Laid-Open No. 11-96649 mentioned above, the power is saved by the inertial rotation during the stop of the disk in the power saving mode, and in addition to this, the drive also applies the reverse voltage to the motor for forced deceleration in such as shifting to the low rotation mode, which consumes extra power.
When applying the reverse voltage to the motor for stop, sometimes the disk is not completely stopped or is rotated in a reverse direction unless the reverse voltage is applied at an appropriate time and voltage corresponding to the current rotational speed and the disk weight. Namely, in the disk drive device disclosed in Japanese Patent Laid-Open No. 11-96649, the inertial rotation is carried out during the stop of the disk in the power saving mode, however, a signal for detecting the number of rotation of the disk is generally such that output from a hall element of the disk motor called FG is converted to pulses and its resolving power is six pulses per rotation of the disk in a three-phase motor which is common in the disk device so that it is difficult to detect the accurate rotational speed immediately before the stop of the rotation. If an ejecting command is issued at this time, the disk cannot be sometimes stopped rapidly and reliably for the reason described above. If the disk is ejected without being reliably stopped, its recording surface is likely to be scratched since existing CD-ROM and DVD-ROM devices are generally of the tray type, and the method of stopping the rotation of the disk more reliably and rapidly and further in the lower power consumption is required.
Moreover, as the method of rapidly decelerating and stopping the disk in the lower power consumption, in the method of decelerating the rotational speed of the disk by bringing the coil of the motor driver IC to the short-circuit condition during the deceleration and utilizing the reverse electromotive force of the motor and the method of compensating for the reduction of the braking force at the portion where the reverse electromotive force at the time of the low rotation is reduced in combination with the reverse brake during the stop of the rotation as disclosed in Japanese Patent Laid-Open No. 9-285174, there is a problem that the reverse electromotive force of the motor is consumed in the driver IC to thereby cause heat generation of the driver IC though not as much as in the method of applying the reverse voltage to the motor for the forced deceleration, and a problem arises that simply using this method is not perfect when the heat generation is desired to be suppressed as much as possible in compact equipment or the like.
The present invention solves the above problems and has its object to provide a disk device and a disk decelerating and stopping method of the disk device which permits selecting the decelerating method with low power consumption when rapid deceleration is not required and permits stopping the disk rapidly and reliably even if need arises for stopping the disk during the deceleration of the disk by the method with the low power consumption.
In order to solve the above problems, the present invention is a disk device having a function of decelerating or stopping a rotating disk wherein a disk motor which rotates the disk selectively carries out a forced decelerating and stopping operation by applying a reverse-direction voltage in order to forcedly decelerate or stop the disk, or a power saving decelerating and stopping operation with lower power consumption than that for the forced decelerating and stopping operation, depending upon the kind of a command at the time of the deceleration or stop. It is also characterized in that when the disk is to be stopped by the power saving decelerating and stopping operation, a reverse-direction voltage is applied for a certain time to reliably stop the disk after a rotational speed of the disk reaches a certain number of rotation. This permits selecting the power saving decelerating and stopping method with low power consumption when the rapid deceleration is not required and permits stopping the disk promptly and reliably even when a need arises for stopping the disk during the deceleration of the disk by the method with low power consumption.
Further, by selectively switching, according as required, between a short-circuit brake which is capable of deceleration at a higher speed, and an inertial rotation which requires longer time for deceleration but generates less heat in motor driving means, as the power saving decelerating and stopping operation, an appropriate decelerating method can be selected in correspondence to each requirement for suppressing heat generation or operating a rapid deceleration.
The invention according to claim 1 is a disk device having a function of decelerating or stopping a rotating disk, comprising: controlling means for switching, depending on the kind of a command upon decelerating or stopping, between carrying out a forced deceleration or stop operation by applying a reverse-directional voltage to a disk motor which rotates the disk so as to forcedly decelerate or stop the disk, and carrying out a power saving deceleration or stop operation with lower power consumption than the forced deceleration or stop operation so as to decelerate or stop the disk.
The invention according to claim 2 is a disk decelerating and stopping method of a disk device which decelerates or stops a rotating disk, comprising selectively switching, depending on the kind of a command upon decelerating or stopping, between carrying out a forced deceleration or stop operation by applying a reverse-directional voltage to a disk motor which rotates the disk so as to forcedly decelerate or stop the disk, or carrying out a power saving deceleration or stop operation with lower power consumption than the forced deceleration or stop operation so as to decelerate or stop the disk.
According to the disk device and disk decelerating and stopping method of the disk device, when the rapid deceleration or stop of the disk is not required, the method with lower power consumption is selected to decelerate and stop the rotation of the disk, so that the rotation of the disk can be decelerated or stopped without consuming extra power.
The invention according to claim 3 is the disk device according to claim 1, wherein upon decelerating or stopping the disk by the power saving deceleration or stop operation, the controlling means controls instruction commanding means which commands the deceleration or stop of the disk to immediately return a response of completion of command execution.
The invention according to claim 4 is the disk decelerating and stopping method of the disk device according to claim 2, wherein upon decelerating or stopping the disk by the power saving deceleration or stop operation, a response of completion of command execution is immediately returned to instruction commanding means which commands the deceleration or stop of the disk.
According to the disk device and disk decelerating and stopping method of the disk device, when the rapid deceleration or stop of the disk is not required, the method with lower power consumption is selected to decelerate and stop the rotation of the disk, so that the rotation of the disk can be decelerated or stopped without consuming extra power, and even if the power saving decelerating and stopping operation is selected, a waiting time for the command completion can be reduced.
The invention according to claim 5 is the disk device according to claim 1 or 3, wherein the disk device further comprises means for carrying out a short-circuit brake by bringing input terminals of a motor coil in the disk motor into a short-circuit condition and utilizing a reverse electromotive force of the motor coil in order for the deceleration or stop of the disk, and the controlling means performs the power saving deceleration and stop operation by carrying out the short-circuit brake.
The invention according to claim 6 is the disk decelerating and stopping method of the disk device according to claim 2 or 4, wherein the power saving decelerating and stopping operation is carried out by performing a short-circuit brake by bringing input terminals of a motor coil in the disk motor into a short-circuit condition and utilizing a reverse electromotive force of the motor coil in order for the deceleration or stop.
According to the disk device and disk decelerating and stopping method of the disk device, the power saving decelerating and stopping operation is carried out by performing the short-circuit brake, so that the rotation of the disk can be decelerated or stopped without consuming extra power.
The invention according to claim 7 is the disk device according to claim 1 or 3, wherein the disk device further comprises means for inertially rotating the disk so as to be decelerated or stopped by friction during rotation, and the controlling means performs the decelerating or stopping operation by the inertial rotation of the disk as the power saving decelerating and stopping operation.
The invention according to claim 8 is the disk decelerating and stopping method of the disk device according to claim 2 or 4, wherein the power saving decelerating and stopping operation is carried out by inertially rotating the disk so as to be decelerated or stopped by friction generated during the rotation.
According to the disk device and disk decelerating and stopping method of the disk device, when the rapid deceleration or stop is not required, the rotation of the disk can be decelerated or stopped without consuming extra power by inertially rotating the disk.
The invention according to claim 9 is the disk device according to claim 1 or 3, wherein the disk device further comprises means for carrying out a short-circuit brake by bringing input terminals of a motor coil in the disk motor into a short-circuit condition and utilizing a reverse electromotive force of the motor coil in order for the deceleration or stop of the disk, and means for inertially rotating the disk so as to be decelerated or stopped by friction generated during the rotation, and the controlling means selectively switches between the short-circuit brake and the inertial rotation of the disk as the power saving deceleration or stop operation to be performed.
The invention according to claim 10 is the disk decelerating and stopping method of the disk device according to claim 2 of 4, wherein the power saving deceleration or stop operation is carried out by selectively switching between a method using a short-circuit brake by bringing input terminals of a motor coil in the disk motor into a short-circuit condition and utilizing a reverse electromotive force of the motor coil in order for the deceleration or stop of the disk, and a method of inertially rotating the disk so as to be decelerated or stopped by friction generated during the rotation.
According to the disk device and disk decelerating and stopping method of the disk device, when the rapid deceleration or stop is not required, the short-circuit brake which is capable of deceleration at a higher speed but involves heat generation or the inertial rotation which requires time for deceleration but reduces heat generation can be selected so that the extra power or heat generation can be suppressed to decelerate or stop the rotation of the disk.
The invention according to claim 11 is the disk device according to claim 7 or 9, wherein the controlling means inertially rotates the disk to be decelerated to a predetermined rotational speed by the friction during the rotation and then applies the reverse-direction voltage for a certain period of time to stop the disk as the power saving deceleration and stop operation.
The invention according to claim 12 is the disk decelerating and stopping method of the disk device according to claim 8 to 10, wherein the power saving deceleration and stop operation is carried out by inertially rotating the disk to be decelerated to a predetermined rotational speed by the friction during the rotation and then applying the reverse-direction voltage for a certain period of time to stop the disk.
According to the disk device and disk decelerating and stopping method of the disk device, the disk can be reliably stopped even if the disk is stopped by the power saving decelerating and stopping operation with low power consumption.
The invention according to claim 13 is the disk device according to claim 11, wherein the disk device further comprises disk weight coefficient measuring means for measuring the weight coefficient of the disk, and a standard of the voltage and time for applying the reverse-direction voltage for a certain period of time is determined based on a measured result by the measuring means.
The invention according to claim 14 is the disk decelerating and stopping method of the disk device according to claim 12, wherein a disk weight coefficient is measured and a standard of the voltage and time for applying the reverse-direction voltage for a certain period of time is determined based on a measured result of the disk weight coefficient.
According to the disk device and disk decelerating and stopping method of the disk device, the disk can be reliably stopped even if the disk with different weight is used when the disk is stopped by the method with low power consumption.
The invention according to claim 15 is the disk device according to any one of claims 1, 3, 5, 7, 9, 11 and 13, wherein when a command is received during the power saving deceleration or stop operation, the controlling means determines, depending on the kind of the command, whether the disk is required to be decelerated from the current speed or stopped in order for executing the command, and if it is determined that the deceleration or stop is required, the controlling means selectively switches either to apply the reverse-direction voltage in order for the forced deceleration or stop, or to decelerate or stop by the power saving deceleration or stop operation.
The invention according to claim 16 is the disk decelerating and stopping method of the disk device according to any one of claims 2, 4, 6, 8, 10, 12 and 14, wherein when a command is received during the power saving deceleration or stop operation, the controlling means determines, depending on the kind of the command, whether the disk is required to be decelerated from the current speed or stopped in order for executing the command, and if it is determined that the deceleration or stop is required, the controlling means selectively switches either to apply the reverse-direction voltage in order for the forced deceleration or stop, or to decelerate or stop by the power saving deceleration or stop operation.
According to the disk device and disk decelerating and stopping method of the disk device, when the rapid deceleration or stop is not required, the power saving decelerating and stopping operation with the low power consumption is selected to decelerate or stop the rotation of the disk so that no extra power is consumed and that the rapid deceleration and stop can be carried out if needs for the rapid deceleration or stop during the deceleration or stop by the power saving decelerating and stopping operation.
The invention according to claim 17 is the disk device according to any one of claims 1, 3, 5, 7, 9, 11, 13 and 15, wherein the disk device further comprises storing means for temporarily storing a certain amount of read data, and in case of receiving a command to read the data stored in the storing means upon decelerating the disk by the power saving decelerating and stopping operation, even if another command is issued thereafter to forcedly decelerate the disk, the controlling means controls not to forcedly decelerate the disk until reading of the data has been completed.
The invention according to claim 18 is the disk decelerating and stopping method of the disk device according to any one of claims 2, 4, 6, 8, 10, 12 and 14, wherein the disk device temporarily stores a certain amount of read data in storing means, and in case of receiving a command to read the data stored in the storing means upon decelerating the disk by the power saving decelerating and stopping operation, even if another command is issued thereafter to forcedly decelerate the disk, the disk is not forcedly decelerated until reading of the data has been completed.
According to the disk device and disk decelerating and stopping method of the disk device, when the rapid deceleration or stop is not required, the power saving decelerating and stopping operation with low power consumption is selected to decelerate or stop the rotation of the disk so that the rotation of the disk is decelerated or stopped without consuming extra power and the data can be reliably read.
The invention according to claim 19 is the disk device according to any one of claims 1, 3, 5, 7, 9, 11, 13 and 15, wherein the disk device is a disk reproducing device which comprises a function of reproducing voice or image data of a CD-ROM, a DVD-ROM device, or the like to be directly output and a function of externally outputting the data read from a recording medium via interface means, and wherein specified commands at the time of the forcedly decelerating and stopping operation include a command to reproduce the voice or image data to be directly output, a command to externally output the data read from the disk via the interface means, and a disk ejecting command.
According to the disk device and disk decelerating and stopping method of the disk device, when the rapid deceleration or stop is not required, the power saving decelerating and stopping operation with low power consumption is selected to decelerate or stop the rotation of the disk so that the rotation of the disk is decelerated or stopped without consuming extra power.
As described above, according to the present invention, when the rapid deceleration or stop of the disk is not required depending on the kind of the command during execution of decelerating or stopping the rotational speed of the disk, the power saving decelerating and stopping operation with low power consumption is selected to decelerate or stop the rotation of the disk, so that the extra power consumption and heat generation can be suppressed. Especially when driving a portable computer provided with a CD-ROM, a DVD-ROM or the like by a battery, the driving time can be extended longer. When the rapid deceleration or stop of the disk is not required in decelerating or stopping the rotation of the disk, the disk motor is not forcedly braked, resulting in extension of the service life of the disk motor.
Further, when the disk is decelerated or stopped by the power saving decelerating and stopping operation, a response of completion of the command execution is immediately returned to the instruction commanding means so that the host computer which commands the deceleration or stop can reduce the waiting time for the command completion as compared with the case where the response of the command completion is returned after having waited for the stopping operation by the power saving decelerating and stopping operation.
The power saving decelerating and stopping operation is executed by applying a reverse-direction voltage to the disk for a certain time after the disk has been inertially rotated and decelerated to a predetermined rotational speed by friction during the rotation, thus allowing the disk to be reliably stopped even when the disk is stopped by the power saving decelerating and stopping operation with lower power consumption.